Signaling system



n EEE@ L. E. COON STGNALING SYSTEM `Fiec March 22. 1924 June 14, 1927.

/m/e/r/or esl/'ei [aan Patented June 14, 1927.

UNITED STATES PATENT OFFICE.

LESLIE E. COON, OF CHATHAM, NEW JERSEY, ASSIGNOR T WESTERN ELECTRIC COM- .PANY, INCORPORATED, 0F NEW YORK, N. Y., A CORPORATION OF NEW YORK.

SIGNALING SYSTEM.

Application led March 22, 1924. Serial No. 701,064.

rlhis invention relates to signaling systems and particularly to selectively operated intercall systems.

An object of the invention is to facilitate the transmission of signals between two or more sta-tions associated with a high resistance line circuit.

The invention is applicable to selectively operated signaling systems employing a plurality of wayslations and is so arranged that any party on the system may, without assistance, call and communicate with any other party without operating the signals at any of the other waystations on the system.

The invention facilitates the transmission of signals in a system of the above character which would ordinarily be attended with diiiiculty because of the high resistance of the line Wires, or the large number of staions thereon, by dividing the system into two or more sections which are connected together through repeater stations.

In a. particular embodiment of the invention, each waystation in the system is provided vwith one or more selectively operated devices each of which is simplexed to ground from the midpoint of an inductive bridge comprising'condensers and impedance coils. A control key is provided at each waystation for discharging and charging the condensers of the bridge at each station on the section through the selectively operated device associated therewith and from a source of energy individual to each line section. The discharging and charging of the condensers of each bridge cause the selectively operated device'associated therewith to be operated for each impulse of discharge or charge current.

iiccording to a feature of the invention,

each repeater station is provided with a polarized relay simplexed to ground from the midpoint of an inductive bridge comprising condensers and impedance coils connected across the terminals of the adjacent line sections. The operation of a control key at any waystation on a given line section, which discharges and charges the condensers in the inductive bridge at each waystation on that section, also causes the condensers in the inductive bridges in series with the repeater relays on that line section to discharge and charge, operating the relays from one l side to the other and baci: again. This closes and opens the repeater relay contacts which in turn operate the selectors on the next line section in a manner similar to that in which the selectors on the first line section were operated.

For the purpose of communication, each waystation is provided with a telephone set and an associated signaling device which is controlled by the selectively operated device thereat. If desired, means may be provided whereby each signaling device, when operatmg, transmits an answer-back signal to the calling station to inform the attendant thereat that the signal at the called station is operating.

The various features and advantages of the invention will be apparent from the consideration of the following description taken in connection with the accompanying drawing which is a diagrammatic illustration of a system embodying the invention.

ln the drawing, 5 and 6 designate a pair of line wires divided into sections W and E joined together at their adjacent ends by means of a repeater R. A plurality of waystations A are associated with the line wires of section 1W and a plurality of similar waystations B are associated with the line wires of section E. For the sake of clearness only two line sections and two waystations have been illustrated, but it will be understood that additional line sections and waystations may be employed as desired.

Each of the waystations A and B is provided with one or more selectively operated signal controlling devices, commonly called selectors, comprising in general polarized operating magnets 7 and stepping means controlled thereby for advancing a step-bystep Contact carrying element 8 into contact-engaging position. The movable contact carrying element 8 is provided with a contact 9 which is adapted to engage a stationary contact l0 when element 8 is advanced a. predetermined number of steps from the normal or start ing position shown in the drawing. The selectively operated signal controlling device illustrated is a code selector of the type disclosed in the United States patent to Field, No. 1,343,256, issued June 15, 1920. A detailed description of the construction and operation of this selector will be found in the Field patent, from which it will be seen that since the selector functions in response to a code or combination of impulses, the selector contacts 9 and 10 of only one station,

namely the called station, are closed in response to a given combination of impulses to operate a signal at only the called station. After the operation of the signal at the called station, another impulse may be sent over the line to cause the element 8 to advance one additional step from which position it is returned to the normal or starting position under the action of a suitable spring. If desired, each selector on the lme may be provided with a second stationary contact 11 as in the above mentioned patent connected in series with the contact 1() for the purpose of transmitting time signals. The contacts 11 are mounted at identical points on all the selectors so that all of the contacts 9 and 11may be closed upon the transmission of a single vtrain of code impulses to operate the signaling `device' at every station simultaneously at an appointed hour. v

. Connected to the line wires and 6 at each of the Waystations is an inductive bridge comprising coils 14, 15, 16, 17, 18 and 19, all of which are mounted upon the same core, and condensers 20 and 21. The coils and condensers of each bridge are included in serialrelation with reference to each other. One side of each of the operating magnets 7 is connected to' ground, the other side being connected with the inductive bridge at a point between the condensers 20 and 21.

Each line section is provided with a battery 23 which is located preferably at or near the extreme end of the section if only one repeater is connected to the section, and is preferably locatedk equidistant from two repeater stations when a repeater is connectedto each end of the section. The battery of each section is connected in simplex of the line wires 5 and 6 by means of a fourpole double-throw switch 27 through ballast lamps 24, a high impedance, low resistance retardation coil l and the windings of a repeating coil 26. The function of the repeating coil is tov offer high impedance to the talking currents during telephone conversation thereby eliminating a loss of transmission due to the passage of some of the talking currents to ground through battery. The ballast lamps have a resistance which increases practically at the same rate as the voltage impressed on them, thereby keeping the current flow from the battery at a minimum. The coil 25, having a high impedance, serves to store the energy in the circuit as in all circuits having a high impedance coil while the condenser and resistance in parallel with it, serve to quench the sparks at contact 30, k31 when they open as will be described hereinafter.

At each way-station there is provided a transmitter key comprising a wheel 29 equipped on parts of its circumference with teeth to actuate contact springs 30 and 31.

rspring 30 is connected between condenser 21 and line-wire 5 and is adapted to be in contact with wheel 29 continuously as the wheel rotates." Contact spring 31 is connected to groundA and is adapted to intermittently make contact with spring 3() as spring 3() is raised by the teeth on wheel 29.

A call bell 32 is connected to each waystation in a normally open local circuit including a battery 33, which circuit is closed by the engagement of the movable contact 9 with either of the stationary contacts 10 or l1.

A telephone set comprising a transmitter 34, a receiver 35, the usual inductance coil 36, and switching devices is provided at each waystation for the purpose of communication. v.

The repeater station R is located at the adjoining ends of line sections W' and E. The repeater comprises a pair of polarized relays 37 and 38. section WV terminate in an inductive bridge comprising windings 39 and 40 of a telephone repeating coil and condensers 4l and 42, while the line wires 5.and 6 of section E terminate in an inductive bridge comprising windings 43 and 44 of the repeating -coil and condensers 45 and 46. The polarized relay 87 is sin'iplexed to ground from a point between the condensers 45 and 46 through contact 5() of polarizedfrelay 38, and the polarized relay 38 is simplexed to ground from a point between the condensers 41. and 42 through contact 51 of polarized relay 37. The polarized relays 37 and 38 are twoposition relays provided with two sets of transfer contact springs which are operated by an armature which remains in the position last operated until it is again operated in the opposite direction. The batteries 23 are connected to each line section in such a way that the initial charge of the condensers 41, 42 and 45, 46 operate relays 38 and 37 to the right as shown in the drawing. Thereafter the alternate discharging and charging of these condensers causes alternate impulses to be sent through the windings of these relays in such a direction :is to attract their armatures first to the left and then to the right to repeat the transmitted nnpulses into the adjacent line section,

The operation of the system is as follows: Normally the condensers 20 and 21 at each waystation are charged to the potential of the battery 23 associated with the line section to which the station is connected, over a circuit which may be traced from battery 23, ballast lamps 24, retardation coil 25, repeatingl coil 26, switch 27, in parallel through line Wires 5 and 6, coils 14, 15, 16 and 17, 18, 19, condensers 20 and 21, Windings of selector magnets 7 to ground. The

The line wires 5 and 6 ofy YC. v

Contact carrying element 8 of the selector is advanced vone step but upon the cessation ot current HOW, when the condensers become charged, element 8 will return to the unoperated position. y Vihen the calling key at any station, say station l, is operated, the Wheel 29 engages the contact spring 89 thus closing a circuit around the condensers 2O andj21. The wheel 29 remains in engagement. With the Contact 30 during the complete operation ot the key. The wheel 29 therefore through contact 30 intermittently engages the contact spring 31 to give the correct combination of impulses to operate r the selector at the station called. The closing and opening of the contact between wheel 29 and contact 31 intermittently connects the bridge formed by the shunt circuit including condensers and 21 and wheel 29 and contact 30 to ground. Upon the grounding oil" this bridge, current flows from ground through battery 23, ballast lamps 24, retardation coil 25, repeating coil 26, switch 27,l in parallel through line wires 5 and 6 of line section E, coils 14 to 19 inclusive, key contacts 29, and 81, to ground. This flow of current causes a voltage drop in the various apparat-us at the waystations and repeater stations associated rwith section E which decreases the potential between the line and ground. The decrease ot' potential causes the condensers 20 and 21 at all the Waystations on section E and the condensers and 46 at repeater station lt to discharge. The current in condensers 20 and 2,1, discharged over a circuit extending from ground, through windings of selector magnets 7, condensers 2O and 21 in parallel,

f Wheel 29 and contact 30 in parallel, Contact 31, to ground, thusl operating the selectors to advance them one step. The selectors at the other Way stations on section E are operated by the corresponding condenser-s discharging over similar circuits.

These. circuits lead from the grounds at the respective stations connected to the upper kcoils of magnets 7, through the condensers 2Q, 21 thereat in parallel, through the coils 14, 1,5, 16 and 17 18, 19 in parallel to the line conductors 5 and 6 ot section E throughthe conductors in parallel connected to the stations on section E, through the coils 14, 1 5, 16 and 17, 18, 19 in parallel at station B contacts 29, 31 to ground.

Each time thevwheel in operating becomes disengaged from the contact 31 the condensers 2O and 21 are charged through thev windings ot selector magnets 7 ver a circuit extending from ground, through battery 23, ballast lamps 24, retardation coil 2,5, repeating coil 26, switch 2 7, line wires 5 and 6 of line section E, coils 14 to 19, inclusive, Wheel Y29 and contact 36, condenser-s 2O and 2 1 in parallel, windings of selector magnets l7, to ground, thus operating the se-A lectors to advance them one step. This also occurs over a similar circuit at the other Way stations. rihese circuits lead from battery 23, ballast lamps 24, coils 25, 26, switch 27, line wires 5, 6 orsection E, coils 14, 15, 16 and 17, 18, 19 in parallel at the respective stations, condensers 20, 21 in parallel, se lector magnets 7 to ground. rlhus, each time contact between wheel 29 and contact 31 Alose and open, the condensers in series with the selector magnets discharge and charge to advance the selectors one step for each impulse oi' discharge or charge current. These impulses alternate in opposite directions to advance the step-by-step contact carrying elements until the contacts 9 and 10 of the selector at the desired station are closed. Upon the cessation oit the last stepping impulse a holding spring 48 on the selector at the called station engages a holding pin on the movable contact carrying elementl 8 to maintain the element 8 in its advanced position with the contact 9 in engagement with the stationary contact 10. The closure of contacts 9 and l() energizes the local circuit ot the carl bell 252 at the called station.

For a detailed description ot the operai n ot the call bells 32 at the various wayice may be had to the United to Field, No. 1,464,099, issued 3. ily referring to this patent,

it wi lf: i that during the operation ot the call the battery will be in- :u'V "fel nnected across the line vlires 5 g t through the medium ot' the inductive e oprising coils 14 to 19 inclusive euse-rs and 21. Upon the enertion ot the winding adjacent contact 57 A bell 32 its arn'iature will so more as close contact 57 and then to open 'The closingl of contact 57 cone `y 88 in series with the conrich is thereupon charged in ac- ,ance with the potential oi' the battery,7 .fg- Consequently, upon the opening et' the '2t 58. a circuit established from the contact 9, stationary contact 10, of bell adjacent contact :37, conto condenser through which cirndcnser 59 is discharged so as to enwinding li?, The energization oi2 this causes current to be generated in windings in the inductive bridge the line conductors and 6 and opve an answeiebacll: signal in the at the calling station@ 'lhe opcalled station mam then comi the operator at the calling station through the respective telephone set;-` 'he telephone nies being communicated trom one lie-esectiou to the other by means ol: the telcone repeating coil comprising windings 89, 40, 43 and 44.

lill

They operation of the transmitter key atv f 44 in parallel, condensers 45 and 46, windings ot' polarized relay 37 and contact 50 of relay 38 to ground, thus operating the relay 37 to open contact 51 and close contacts 52 and 53. The contacts 52 and 53 of relay 37 in closing complete a circuit trom ground, through battery 23 of line section WV, ballast lamps 24, retardation coil 25, repeating coil 26. switch 27, line wires and G, repeating coils 39 and 40, contacts and 53 of polarized relay 37, to ground. This low ol current causes a voltage drop in the various apparatus at the waystations associated with line section Wr which decreases the potential between the line and ground. This decrease of potential causes the condensers and 21 at station A and all the other waystations on section 1V to discharge through their associated selector magnets 7 and contacts 52 and 53 of relay 37. Upon the subsequent operation of relay 37 the contacts 52 and 53 are opened, thus causing the condensers 20 and 21 to charge through their associated selector' magnets. Thus the alternate closing and opening of contacts 52 and 53 of polarized relay 37 causes the discharging and charging of the condensers in series with the selector magnets at the waystations associated with line section W' to advance the selectors one step for each impulse of discharge or charge current.

From the above it will be seen that each time the contact 31 of the transmitter at station B closes and opens, the condensers in series with the selectors at each waystation on line section E discharge and charge, causing the selectors at the waystations associated with liuc section E to advance one step for each impulse of discharge or charge current. Also the condensers and 46 discharge and charge, operating the polarized relay 37 from one side to the other and back again. This closes and opens the contacts of polarized relay 37 which, in turn, cause the operation of the selectors at all the waystations on line section 1V.

The transmitter key at station A and all the other waystations on line section WV also function in the manner described above to discharge and charge the condensers 20 and The decrease ot potential caused by theV 21 at the various waystations of line section 1V as well as the condensers 41 and 42 in the inductive bridge of that line section. The condensers 41 and 42 discharge through the windings ot' polarized relay 38 and contact 51 of relay 37, to ground, thus operating relay 38 to open contact 50 and close contacts 54 and 55 to repeat the transmitted impulses to the line section E. In charging, the condensers 41 and 42 operate the relay 38 to open contacts 54 and 55 and close contact in a manner similaito that described in connection with the operation of polar ized relay 37. y

The windings of polarized relay 37 are connected to ground through the contact 50 of relay 38 in order to prevent the relay 37 from operating as the relay 38 closes its contacts 54 and 55. By means of this arrangement, the condensers 45 and 46 are prevented from discharging upon the closure of contacts 54 and 55 of relay 38 since the contact 50 in the discharge path of these condensers is open at such time. If the relay 37 Were permitted to operate and close its Contact 53 during the operation of rela. 38 when impulses are being transmitte fromV section 1V. the system would not function because the contact 53 would parallel the contact between wheel 29-and contact 31 at station A and no charging current would How through the condensers on line section W to operate the selectors and relay 38 when the Selector key contacts 29 and 3l at station- A were opened. Similarly, the windings of relay 38 are connected to ground through the contact 51 of relay 37 to prevent the discharge of condensers 41 and 42 and the consequent operation of relay 38 when the relay 37 closes its contacts 52 and 53, when impulses are being transmitted from section E.

It will be seen that the repeater' station R permits the system to be operated over high resistance line wires equip ed with a large number of waystations, an allows each line section to be operated with a comparatively low potential between the line Wires and ground. This reduces the strain on the apparatus in the circuit and also reduces the danger of shock to the maintainers.

Since many changes may be made in the system herein shown and described Without departing from the spirit of the invention, it is to be understood that the invention is not to be limited thereto except as defined by the sco e of the appended claims.

hat is claimed is:

1. In a signaling system, a line circuit comprising a plurality of line sections, a bridge including inductive and capacity devices connected across each of said line sections, a selector connected between ground and the midpoint of each bridge, a source of current individual to each line section, bridges including inductive and capacity devices connected across the terminals of adjacent. line sections, a polarized relay connected between. ground and the midpoint of each of said last mentioned bridges. means including the source of current for discharging and charging the condensers bridged across each line section to operate the selectors and polarized relays thereon, and means controlled by said polarized relays for discharging and charging the condensers in the bridges associated With the selectors on the adjacent line section.

2. In a signaling system, a line circuit comprising a plurality of line sections, a. bridge including inductive and capacity devices connected across each ot said line sections, a selector connected between ground and the midpoint of each bridge, a source of current individual to each line section7 bridges including inductive and capacity devices connected across the terminals of adjacent line sections, a. polarized relay connected between ground and the midpoint of each of said last mentioned bridges, means including the source of current for discharging and charging the condensers bridged across each line section to operate the selectors and polarized relays thereon, means controlled by said polarized relays for discharging and charging the condensers in the bridges associated with the selectors on the adjacent line section, and means controlled by each of said relays 'lor preventing the discharge of the condensers in the bridge associated with the polarized relay on the adjacent line section.

3. In a signaling system, a line circuit comprising a plurality of line sections, means for inductively connecting said scctions, repeater stations connecting adjacent line sections, a plurality of selectors associated with each line section, a pair ot relays at each of said repeater stations connected respectively with adjacent line sections, means for energizing and deenergizing each .line section for operating the selectors and repeater relay thereon, means controlled by said repeater relays for energizing and deenergizing the adjacent line section to operate the selectors thereon, and means controlled by each relay at a repeater station for disconnecting the other relay thereat from its line section.

In Witness whereof, I hereunto subscribe my name this 19th day of March, A. D. 1924.

LESLIE E. COON. 

